My boyfriend thinks he's having sex with a kid?

I'm 18 he's 28. Because of the age gap, sometimes he told me he felt guilty sometimes because he thinks he's having sex with a kid... The legal age here is 16 and I'm not a kid but what do I tell him now? We love each other and everything but sometimes he just couldn't help feeling guilty...

Since when tf is what people did in the olden days the final say on what's right? They also burned people alive for witchcraft at some point in fairly recent history, do you propose its ok if I burn my neighbor?